The proposed research provides a systematic, comparative investigation of the underlying temporal processes of immigrant assimilation, i.e., the integration and convergence of immigrants with the behavior and status attainments of the native born. Most studies have focused on only 1 or 2 indicators of assimilation at a time, and current scholarship on immigrant assimilation is fragmented along disciplinary boundaries, with different disciplines focusing on different outcomes and employing different temporal specifications. Immigrant assimilation takes place across multiple dimensions of time: across generations, with growing duration within the first generation, across ages at arrival, or other dimensions. Rather than simply assume a temporal specification for immigrant assimilation, this should be made the object of inquiry. The specific aims of the proposed research are to: (1) Review the types of temporal specifications employed in the literature for a diverse set of assimilation outcome variables, and select measures of acculturation, economic integration, residential integration, civic incorporation, and health practices. (2) Analyze and compare effects of duration and generation on the range of outcome variables, also contrasting cross-sectional, cohort longitudinal analysis, and intergenerational mobility. (3) Compare age at arrival gradients for each outcome and their effects on assimilation, and test for similarities between second generation and young first generation. (4) Test for variations across historical periods in the temporal dynamics of assimilation. (5) Investigate differences and similarities across different ethnic/national origin groups.